JPH09125771A - Remote keyless-entry for usage for automobile and inactivating system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To extend a transmission distance, conquer a problem of confidentiality, and lengthen the service life of a battery. SOLUTION: A key can perform two-way communication with a microprocessor control part MCU of a vehicle. The key performs transmission by two different frequencies. High frequency transmission is used for remote control such as to open and close a locking device of a door. The key is inserted into an ignition safety device of the vehicle, and when two-way communication between an automobile and the key is performed, low frequency transmission is used. A microprocessor is not used in a key circuit. The transmission is enciphered, and a theft is prevented. A capacitor 54 is charged by using the low frequency transmission sent from the vehicle, and a battery 52 is recharged, and the service life of the battery is lengthened. The capacitor supplies electric power to a circuit of the key circuit 41.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates generally to motor vehicles and more particularly to remote keyless entry and immobilization systems for motor vehicles.
mobilization system).

[0002]

2. Description of the Related Art The use of electronic circuits in automobiles has become widespread and has spread to all aspects of automobile driving. For example, electronic circuits manage everything from the operation of the drivetrain of a vehicle to the environment within the vehicle interior. Automotive accessory afte
One of the systems initially developed by rmarket)
There is a remote keyless entry system. This remote keyless entry system is a transmission circuit that controls a door locking system of a vehicle from a remote location. For example, it allows a person to lock or unlock the door or trunk by walking on or off the car and pressing an activation button on the transmitter. The transmitter is usually housed in a small plastic housing and attached to a key chain that easily fits in your pocket or purse. A receiver circuit is installed in the vehicle to receive the transmitted signal and enable or disable the locking system.

Another system designated for automobiles in Europe is an immobilization system for disabling automobiles. For example, one proposed immobilization system utilizes a specific code that is keyed into the vehicle. Each code is unique to each car, this code is 1
Since there are over trillion types, it is unlikely that a random code can be entered. If the code entered by the key matches the code stored in the vehicle's computer system, the vehicle is enabled and ready for use. Attempts to use the vehicle by unauthorized means without entering the (hot-wired) code will render the vehicle inoperable because it will disable the vehicle's fuel pump, fuel injectors, spark generators, transmission and steering system. Become.

It would be of great benefit if a system could be developed that combines remote keyless entry with immobilization to increase security and reduce the number of components required for manufacture.

[0005]

Remote keyless entry systems for automobiles typically use small plastic
It is housed in a case. This small plastic case, usually part of a key chain, is shaped to fit between your thumb and forefinger. The thumb is used to press a button to activate the device. Plastic cases are not ideal because the hand holding the device interferes with the transmission of signals. plastic·
The code is transmitted by a transmitter in the case and received and verified by a receiver located in the vehicle and coupled to the electromechanical locking system. More specific information is included in the transmission, such as information regarding which door locking device is open or closed, and information that separates a particular locking device (eg, trunk locking device).

In general, remote keyless entry systems include a transmitter and a receiver as well as a microprocessor and, for example, an electrically erasable programmable lead
Only Memory (EEPROM: Electrically Erasable
Programmable Read Only Memory) or flash
And some form of non-volatile memory, such as memory.
A microprocessor or microcontroller controls the operation of the remote keyless entry system. The non-volatile memory is used to store a code unique to each device and operating software. With read / write non-volatile memory, code can be written to the unit at any time and later modified. Both the microprocessor and the non-volatile memory are expensive components of the remote keyless entry system, which increases manufacturing costs.

Security is a major problem in remote keyless entry systems because the code required to open the vehicle door is broadcast. When a signal is broadcast, it can be intercepted by others. Those who are familiar with the technology of remote keyless entry systems may use the intercepted transmissions to open the vehicle into the vehicle and help steal it. Similarly, an immobilization system that utilizes a fixed code to enable a vehicle may not be suitable for integration with a remote keyless entry system due to the potential for code interception during transmission.

Another factor in transmitter-based automotive activation systems is that they are battery powered. The transmission circuit depletes the battery in a short time and requires frequent battery replacement. Further, as the battery gets weaker, the transmission distance becomes shorter, which may cause a situation in which the vehicle is not locked even if the device is activated (depending on the distance from the vehicle). In this case it would have been locked if a fully charged battery was used. Automobile manufacturers want to ensure at least 10 years of battery life on remote keyless entry and immobilization systems, and under normal operation, little or no reduction in transmission distance. Current battery technology does not provide 10 years of battery life.

[0009]

SUMMARY OF THE INVENTION A remote keyless entry and immobilization system is disclosed herein which maximizes transmission distance, overcomes security issues and prolongs battery life. Maximizing the transmission distance is achieved by incorporating an antenna that is not shielded by the hand during operation.
In addition, security is secured by using a cryptographic code system unique to each operation. The key battery is
The battery life is increased by charging the battery every time the key is used in the ignition lock and the vehicle is driven. Further, the use of the dedicated microcontroller in the key transmission element is abolished, and the existing automobile microcontroller is used in the automobile to reduce the cost.

[0010]

1 is a diagram of a key 11 forming the transmitter of a remote keyless entry and immobilization system. In the preferred embodiment, a remote keyless entry and immobilization system is provided for use in an original equipment manufacturer (OEM) for incorporation into the vehicle electronics.
Manufacturer) is created for. The transmitter is the integrated circuit 12 housed in the handle portion of the key 11. In the preferred embodiment, the key 11 is an automobile ignition key. Key 11
A control button 13 is arranged on the handle portion of the.
The control button 13 enables and disables functions such as driver door locking, passenger door locking, trunk opening, and panic / alarm. The part of the key 11 that fits into the mechanical locking device serves as the antenna of the transmitter. The antenna is unobstructed when you press the button, so
Note that the maximum radiation pattern is receivable by the vehicle 14.

As mentioned above, prior art immobilization systems enter a code into the vehicle, which causes a fuel pump, fuel injector, spark generation, transmission,
And is designed to enable engine functions such as steering systems. If the theft occurs and the code is not entered into the microprocessor control unit (MCU),
The car is disabled by the MCU immediately or within a short time after the theft. Since the fixed code can be intercepted and used to enable the vehicle, it is not safe to equip a fixed code based immobilization system with a transmitter.

FIG. 2 is a diagram showing elements of a remote keyless entry / immobilization system for a vehicle. The key 21 activates the system either remotely or when coupled to an ignition lock 22. The antenna 23 in the vehicle receives the transmission from the key 21. Antenna 23
Are coupled to receiver circuit 24 and MCU 26.
The MCU 26 is an electronic processor for controlling various operating aspects of the vehicle. In the preferred embodiment, the MCU 26
Is composed of an engine control module 27 and a vehicle body control module 28. The engine control module 27 monitors and controls the engine. Engine control module 27
Controls functions used in immobilization systems to disable the vehicle in the event of theft, such as fuel pumps, fuel injectors, ignition systems, transmissions, and steering systems. The body control module 28 activates the panic / alarm 31 and the door and trunk locking device 32.

In the preferred embodiment, the key 21 transmits information to the vehicle on an ultra high frequency (UHF) 315 MHz carrier frequency. The key 21 can transmit the code to receivers in the vehicle at a distance of 10 meters or more. The signal transmitted from the key 21 is encrypted for confidentiality. The encryption prevents receiving a transmission and using it to enable normal operation of the vehicle due to the fact that the code transmitted changes from transmission to transmission. For example, a vehicle owner uses a remote keyless entry / immobilization system to arm the system and lock the vehicle when it reaches its destination. The thief receives the transmission with the hope that it can apply it again to the system to allow normal operation of the vehicle. The encrypted code changes with each transmission. Since the vehicle expects to receive a different code, the received transmission cannot be reapplied to the vehicle to unlock the vehicle or release the engine immobilization system.

One form of encryption technique applicable to remote keyless entry / immobilization systems utilizes a polynomial algorithm to generate the transmit code. The polynomial algorithm uses the previous code to generate the next code to receive. Therefore, the current code is generated from all the previous codes, so the polynomial algorithm provides good protection. Even if someone obtains the polynomial algorithm, the current code cannot be generated unless the initialization code that started the code sequence, that is, the seed coe is also obtained. Moreover, the number of possible different codes is very large (eg, trillions of combinations), so random selection of codes is unlikely to hit. Also, the exhaustive approach, which sends the code until a suitable code is found, is not feasible because there is a large amount of code and it takes a long time. The remote operation of the key 21 is one-way communication.
Transmits information and the receiver 24 in the vehicle receives this information and acts according to the instructions contained therein. When the key 21 is arranged on the ignition lock 22,
It receives information from the MCU 26 and returns a response (sends a response). The ignition lock 22 includes a switch that is enabled to activate the vehicle when the key rotates the ignition lock 21 and otherwise detects the key. The vehicle is immobilized by the engine control module 27 until the MCU 26 sends new information to the key 21 and the key 21 returns the code output, which is confirmed by the MCU 26 to be valid. Once confirmed, the engine control module 27 enables the fuel pump, fuel injectors, ignition system, transmission, starter, etc. to enable the driver's use of the vehicle.

In the preferred embodiment, communication between the MCU 26 and the key 21 (when placed in the ignition lock) is accomplished by low frequency transmission over a very limited distance (typically 10 centimeters). To do. A transmission frequency of about 125 kilohertz is used. The low frequency transmitted energy is
It is also used to power the integrated circuits in the key 21. Inductive coupling is used to send and receive signals at 125 kilohertz.

FIG. 3 is a block diagram of a key circuit 41 for remote keyless entry and immobilization confirmation. The key circuit 41 is built in the ignition key of the vehicle. Key circuit 41
The cost savings identified above is in the absence of the microprocessor or EEPROM memory typical of prior art remote keyless entry systems. The key circuit 41 includes a power management circuit 42, low frequency read / write
Encoder / decoder circuit 45, key sequencer circuit 4
6, a cipher generation circuit 47, and a UHF transmission circuit 48. The cipher generation circuit 47 provides functions common to both remote keyless entry configurations and immobilization configurations. Other peripheral elements built in the key include UHF antenna 4
9, keypad 51, battery 52, low frequency antenna 5
3 and capacitor 54.

In the preferred embodiment, the UHF antenna 49 is
The metal blade of the key, which is inserted into the ignition lock of the vehicle. The keypad 51 is built in the handle portion of the key. The keypad 51 is a button or switch that is pressed when sending a command for remote operation such as locking / unlocking the trunk of the vehicle, all doors, or the driver's door only. The battery 52 is a key circuit 41 for remote control only.
A battery housed in a key that powers the. The low frequency antenna 53 couples the key circuit 41 to the vehicle's microprocessor control unit (MCU) when the key is inserted into the ignition switch and rotated to start the vehicle. Low frequency antenna 5
The secondary function of No. 3 is to charge the capacitor 54 by low frequency transmission from the vehicle. The capacitor 54 is used to store charge for a short period of time, power the key circuit 41, and recharge the battery 52.

The key circuit 41 is capable of transmitting a remote control signal and two-way communication between the key circuit 41 and the MCU of the automobile when the key is installed in the ignition lock. The key sequencer 46 is connected to the keypad 51,
The control signal for remote operation is supplied to the circuit of the key circuit 41. The cipher generator 47 is connected to the key sequencer 46 and generates an encrypted code to verify the validity of the key on the vehicle. The UHF transmitter 48 is connected to the cipher generator 48 for remote delivery of the encrypted code. U
The HF transmitter 48 is connected to the UHF antenna 49,
Transmit at F frequency. In the preferred embodiment, a UHF frequency of 315 MHz is used.

The low frequency read / write encoder / decoder circuit 45 is connected to a cipher generator 47 for bidirectional processing of information. Low frequency read / write
The encoder / decoder circuit 45 encodes and decodes information for low frequency transmission when the key is inserted into the ignition lock of the vehicle. The low frequency antenna 49 is connected to the low frequency read / write encoder / decoder circuit 45. In the preferred embodiment, the low frequency antenna is tuned to a frequency of 125 kilohertz.

The power management circuit 42 uses the key circuit 4
Controls whether power is supplied to 1. Power management circuit 42
Is composed of a capacitor energy management circuit 43 and a battery energy management circuit 44. The low frequency antenna 53 is connected to the capacitor energy management circuit 43 and uses the transmission from the vehicle to charge the capacitor 54. Capacitor energy management circuit 43 couples capacitor 54 to power key circuit 41 when the key is inserted in the ignition lock of the vehicle. Capacitor 54 powers low frequency read / write encoder / decoder circuit 45, key sequencer 46, and cipher generator 47, as indicated by the dashed power line 55 from capacitor energy management circuit 43.

The battery energy management circuit 44 includes a battery 52,
Keypad 51, capacitor / energy management circuit 43,
And the cipher generator 47. The battery energy management circuit 44 supplies power to the key circuit 41 when a key of the keypad 51 is pressed for remote operation. The battery energy management circuit 44 connects the battery 52 to the key sequencer 46, the cipher generator 47, and the U as shown by the dashed power line 56.
Coupled to HF transmitter 48.

The battery energy management circuit 44 detects the voltage of the battery 52 and supplies a status signal to the cipher generator 47 when the battery voltage is low. Cipher generator 47 and low frequency read / write encoder / decoder circuit 45
The MC of the car when the key is inserted in the ignition lock
Notify U that charging is required. In the preferred embodiment, the vehicle emits a preamble for transmission which is stored on capacitor 54 and is stored in capacitor energy management circuit 43 and battery energy management circuit 4.
4 to the battery 52.

FIG. 4 is a block diagram of the interface circuit 61 in the vehicle for verifying the validity of the key code, ie, the remote key operation for activating a portion of the vehicle. Microprocessor control unit (MC
U) 62 is built into most modern vehicles to control vehicle operation. Antenna 63 receives a transmission from a remotely operated key. The low frequency antenna 64 is
It transmits energy and information and receives information from a key that is inserted in the ignition lock of a vehicle.

The interface circuit 61 comprises an output buffer 65, a UHF receiver 66, an interface control sequencer 67, an input / output buffer 68, and a low frequency read / write circuit 69. The interface control sequencer 67 controls the operation of the interface circuit 61. More specifically, it processes information transfer with the MCU 62. The UHF antenna is connected to the UHF receiver 66,
Receive transmissions from remotely operated keys. The UHF receiver 66 receives the information transmitted remotely from the key and connects to the output buffer 65. Microprocessor 62 also controls many other functions and may not immediately respond to transmissions. The output buffer 65 is connected to the MCU 62, and until the MCU 62 receives a transmission and becomes responsive,
The transmission received from the HF receiver 66 is stored. The interface control sequencer 67 is connected to the UHF receiver 66 and the MCU 62. The interface control sequencer 67 and the MCU 62 respond to each other so that the transmission stored in the output buffer 65 is M
Confirm that the CU62 is successfully supplied.

Two-way communication between the key and the vehicle takes place when the key is inserted in the ignition safety device of the vehicle.
Both the key and the car transmit at low frequencies. The low frequency antenna 64 transmits and receives low frequency signals. The low frequency antenna 64 is connected to the low frequency read / write circuit 69. The interface control sequencer 67
A control signal is supplied to the low frequency read / write circuit 69 and the input / output buffer 68 to control the transfer of information. The input / output buffer 68 is connected between the MCU 62 and the low frequency read / write circuit 69. Input / output buffer 6
8 stores information until it is coupled to MCU 62 or low frequency antenna 64. The operation of the remote keyless entry and immobilization system is described in FIGS.
Can be best explained by using the block diagram of Referring to FIG. 4, remote operation is started when a key of the keypad 51 is pressed. The battery energy management circuit 44 is enabled and the battery 52 is replaced by the key sequencer 4
6, cipher generator 47, and UHF transmitter 48. The key sequencer 46 generates a control signal for the operation of the key circuit 41 and outputs a command to cause the vehicle to perform the task corresponding to the pressed key of the keypad 51. The cipher generator 47 generates a cipher code for checking the validity of the remote control. The encrypted code is only valid for the current transmission. The car predicts a different code for the next action. The encrypted code and instructions are U
Transmitted by HF transmitter 48 and UHF antenna 49.

Referring to FIG. 4, the transmission from the key is UHF.
It is received by the antenna 63. The low frequency read / write circuit 69 receives this transmission and outputs this transmission to the input / output buffer 68. The interface control sequencer 67 interfaces with the MCU 62 and downloads this transmission. Once the MCU 62 has obtained the transmission, the encryption code is verified, if correct the instruction is executed (eg lock all doors), otherwise ignored.

Please refer to FIG. 3 and FIG. A second type of action occurs when the key is inserted into the ignition lock of the vehicle. In the preferred embodiment, the key is turned to allow the vehicle to start. Turning the key activates the switch in the ignition lock and activates the MCU 62. The MCU 62 performs transmission for starting communication via the input / output buffer 68, the low frequency read / write circuit 69, and the low frequency antenna 64. The power management circuit 42 detects this transmission and couples the capacitor 54 to be charged by this transmission. Capacitor 54 is coupled through capacitor energy management circuit 43 to power low frequency read / write encoder / decoder circuit 45, key sequencer 46, and cipher generator 47.

The cipher generator 47 supplies the encrypted code to the low frequency read / write encoder / decoder circuit 45. The encrypted code further includes the low frequency antenna 53.
Through the interface circuit 61. The low frequency antenna 64 receives the transmission from the key and couples it to the low frequency read / write circuit 69. The transmission is then stored in the I / O buffer 68 and sent to the MCU 62. The MCU 62 confirms the validity of the encryption code sent by the key. If the encryption code is valid, MC
The U62 enables the vehicle to start by enabling various systems such as a starter, ignition system, and fuel supply system.

In the preferred embodiment, MCU 62 provides a new seed code for the cryptographic polynomial stored in cipher generator 47. With this new seed code, it is possible to generate a new encrypted code string for each remote use. Changing the seed code on a regular basis reduces the chance of someone copying the changing code. New seed code and encryption code is MCU
Sent by 62 and stored in the input / output buffer 68. The low frequency read / write circuit 69 transmits the seed code and the encryption code to the key via the low frequency antenna 64. The low frequency antenna 53 receives the transmission and couples it to the low frequency read / write encoder / decoder circuit 45. The low frequency read / write encoder / decoder circuit 45 transmits the transmission to the cipher generator 47.
, Where the cryptographic code is validated and the new seed code is replaced with the old seed code.

The battery energy management circuit 44 detects the battery voltage and supplies a battery status signal to the cipher generator 47. If the battery status signal indicates to recharge the battery, the cipher generator 47 sends this status to the vehicle. The low frequency read / write encoder / decoder circuit 45 couples this information to the low frequency antenna 53.
The interface circuit 61 receives the information about the low battery voltage and returns the "preamble" to the key. Then
The key supplies energy to the capacitor energy management circuit 43 to charge the capacitor 54 and the battery 52.

By now it should be appreciated that a remote keyless entry and immobilization system for an automobile has been described. Keys for remote keyless entry and immobilization systems do not require microprocessor circuitry or non-volatile memory, which allows for reduced manufacturing costs. The system utilizes high frequency transmissions for remote operation and low frequency transmissions for communication between the key and the vehicle when the key is inserted in the ignition lock. Since the transmission is encrypted, it greatly reduces the possibility of theft and allows the immobilization system to be integrated into the key. The key is powered by a battery and a capacitor that receives energy from the vehicle's low frequency transmissions. Charging the battery using low frequency transmission extends the battery's life and achieves the 10 year life cycle desired by car manufacturers.

While we have shown and described specific embodiments of the present invention, further modifications and improvements will occur to those skilled in the art. Therefore, it will be understood that the invention is not limited to the particular forms shown. Furthermore,
All modifications that do not depart from the spirit and scope of the invention are intended to be covered by the appended claims.

[Brief description of the drawings]

FIG. 1 shows a key for transmitting information to a microprocessor control unit (MCU) of an automobile according to the present invention.

FIG. 2 shows a device provided in a vehicle for remote keyless entry and immobilization confirmation according to the present invention.

FIG. 3 is a block diagram illustrating a key circuit contained within a key for a remote keyless entry and immobilization system according to the present invention.

FIG. 4 is a block diagram of a vehicle interface circuit and a microprocessor control unit according to the present invention.

[Explanation of symbols]

11 key 12 integrated circuit 13 control button 14 automobile 21 key 22 ignition lock 23 antenna 24 receiving circuit 26 MCU 27 engine control module 28 main body control module 31 panic / alarm 32 door and trunk lock device 41 key circuit 42 power management circuit 45 low frequency Read / write encoder / decoder circuit 46 Key sequencer circuit 47 Cipher generation circuit 48 UHF transmission circuit 49 UHF antenna 51 Keypad 52 Battery 53 Low frequency antenna 54 Capacitor 56 Power line 61 Interface circuit 62 Microprocessor control section 63 Antenna 64 Low frequency antenna 65 Output Buffer 66 UHF Receiver 67 Interface Control Sequencer 68 Input / Output Buffer 69 Low Frequency Read / Write Circuit

Claims (3)

[Claims] 1. A remote keyless entry and immobilization system for a vehicle, wherein the communication between the key (11) and the vehicle includes an encryption code that changes with each transmission, thereby stealing. A remote keyless entry and immobilization system, which protects the vehicle from being enabled for use by transmission. 2. A remote keyless entry and immobilization system for an automobile comprising: a key circuit (41) housed within a key for transmitting and receiving information: a key sequencer (4).
6); a low frequency read / write encoder / decoder circuit (45) responsive to the key sequencer (46) and communicating with a microprocessor control unit (26) (MCU) of the vehicle; the key sequencer (46) A low-frequency read / write encoder / decoder circuit (4) for encrypting a code in response to
5) a cipher generator (47) coupled to 5); and an ultra high frequency (UHF) transmitter (48) responsive to the cipher generator (47) for remotely transmitting information from the key. Remote keyless entry and immobilization system, characterized in that it comprises a key circuit (41); 3. A method of combining a vehicle remote keyless entry system and a vehicle immobilization system: said vehicle and key (1) so that a different code is required for each transmission.
1) encrypting transmissions to and from which the stolen transmissions are retransmitted to the vehicle without unlocking and enabling the vehicle for use.